Device for regulating the supply of pressurized fluid of two circuit systems having at least two pumps of constant cubic capacity

ABSTRACT

This invention relates to a device for supplying two circuits 10 and 11 by means of four pumps 2, 3, 4, 5. The delivery pressures of the two circuits act on the control jacks 38, 39, 43 and 44 of two &#39;&#39;&#39;&#39;cutting off&#39;&#39;&#39;&#39; distributors which, when they are actuated, put pump 4 and/or pump 3 in communication with the reservoir 6, avoiding for the engine 1 an excessive load exceeding its maximum power. An application of the invention is the achievement of a high efficiency of a supply circuit.

U te States Patent [1 1 1 [111 3, .iacquot Dec. 9, 1975 [54] DEVICE FOR REGULATING THE SUPPLY 3,716,308 2/1973 Kobald 417/286 PRESSURIZED FLUID OF TWO 3,723,026 3/1973 Soyland et al. 417/286 CIRCUIT SYSTEMS HAVING AT LEAST TWO PUMPS 0F CONSTANT CUBIC Primary Examiner-William L. Freeh CAPACITY Assistant ExaminerG. P. LaPointe [75] Inventor: Jean Noel Jacquot, Saint Soupplets, Attorney Agent or Flrm Mason Fenwlck &

France Lawrence [73] Assignee: Poclain, Le Plessis-Belleville, France [22] Filed: Jan. 23, 1975 [57] ABSTRACT PP N05 544,200 This invention relates to a device for supplying two circuits and 11 by means of four pumps 2, 3, 4, 5. Foreign Application Priority Data The delivery pressures of the two circuits act on the Jan. 30, 1974 France 74.03096 Control jacks 38, 39, 43 and 44 of two Cutting distributors which, when they are actuated, put pump 52 US. (:1. 417/286 4 ahd/or P p 3 in communication With the reservoir 51 Im. cl. F04B 49/00 avoiding for the engine 1 an excessive load [58] Field of Search 417/286, 287, 288, 426, exceeding its maximum p 417/428 An application of the invention is the achievement of a high efficiency of a supply circuit.

[56] References Cited UNITED STATES PATENTS 4 Claims, 2 Drawing Figures 3,695,783 10/1972 Soyland et a]. 417/286 US. Patent Dec. '9, 1975 Sheet 1 of2 3,924,971

US. Patent Dec. 9, 1975 Sheet 2 of2 3,924,971

DEVICE FOR REGULATING THE SUPPLY OF PRESSURIZED FLUID OF TWO CIRCUIT SYSTEMS HAVING AT LEAST TWO PUMPS OF CONSTANT CUBIC CAPACITY The present invention relates to a device for regulating the supply of pressurised fluid of two circuit systems having at least two pumps of constant cubic capacity.

Pressurised fluid feed devices are already known which, by means of a plurality of pumps of constant cubic capacity, driven by a single Diesel engine, feed two circuit systems.

It often appears economically advantageous to choose a Diesel engine of limited power and even of maximum power lower than the sum of the maximum powers of the various pumps. It is obvious, when these latter conditions are combined, that a device must be provided which limits the power required for driving the pumps, to the value of the maximum power of the motor.

One of these devices consists in making one or more of the pumps normally supplying each of the circuits, without pressure to a fluid tank. This communication with the tank, of the delivery of the pumps, is moreover effected by controlling distributors disposed in the delivery conduits, control by the delivery pressure itself of each circuit. Nevertheless, the said control does not allow optimum use of the power of the Diesel engine, particularly in the case of the delivery of all the pumps being able to be directed towards one of the circuits only.

In order to obviate the disadvantage of the known solutions applying to this latter case, the invention proposes a new type of control of the distributors, by means of a judicious combination of the effects of the pressures of the two circuit systems. In this manner, it enables the connection between the delivery of one pump and the circuit system connected thereto to be maintained, for a pressure in this circuit which may be greater than the cut-off pressure beyond which, in the known devices, said delivery is placed in communication with the tank.

To this end, the invention seeks to provide a device feeding two circuit systems with pressurised fluid, constituted by:

a fluid tank,

a first group of pumps, each with constant flow,

a first of the two circuit systems,

a first feed conduit connecting a first pump, belonging to the first group of pumps, to the first circuit system,

a first two-way distributor, disposed in the first feed conduit, ensuring, in its first position, the continuity of the first feed conduit and, in its second position, the communication of that part of the feed conduit included between the first pump and the first distributor with the tank,

a second group of pumps, each with constant out flow,

the second of the two circuit systems,

a second feed conduit connecting a second pump, belonging to the second group of pumps, to the second circuit system,

a second two-way distributor, disposed in the second feed conduit, ensuring, in its first position, the continuity of the second feed conduit and, in its second position, the communication of that part of the second feed 2 -conduit, included between the second pump and the second distributor, with the tank,

a third two-way distributor, disposed in the second feed conduit between the second distributor and the second circuit system, and

a connecting conduit which connects the third distributor to that part of the first feed conduit included between the first distributor and the first circuit system.

The third distributor, in its first position, establishes communication between the second distributor and the second circuit system and, in its second position, establishes communication between the second distributor and the connecting conduit and obturates that part of the second feed conduit connected directly to the second feed circuit.

First and second control members, as well as a first return member, are coupled to the first distributor, each of the first and second control members having an effect opposing that of the first return member, and said latter having an effect tending to place this first distributor in its first position, whilst third and fourth control members, as well as a second return member, are coupled to the second distributor, each of the third and fourth control members having an effect opposing that of the second return member, and said latter having an effect tending to place this second distributor in its first position.

In addition,

a first control conduit connects that part of the first feed conduit, included between the first distributor and the first circuit system, to the first control member,

a second control conduit connects that part of the second feed conduit included between the second distributor and the third distributor to the second control member,

an auxiliary conduit connects that part of the first feed conduit included between the first distributor and the first circuit system to that part of the second feed conduit included between the second and third distributors, a shuttle valve being disposed in said auxiliary conduit,

a third control conduit connects that part of the second feed conduit included between the second and third distributors to the third control member,

a fourth control conduit connects the output of the shuttle valve to the fourth control member.

Finally, the pumps of the first and second groups of pumps are coupled to a single drive motor, of which the maximum power is lower than the sum of the maximum powers of the various pumps.

The following arrangements are preferably adopted:

the first and second control members each consists of a hydraulic ram the ratio of the cross-section of said rams is equal to the ratio of the sum of the cubic capacities of the pumps of the first group and the sum of the cubic capacities of the pumps of the second group, less the value of the cubic capacities of the second pump of the said second group respectively.

the third and fourth control members each consists of a hydraulic ram the ratio of the cross-sections of said rams is equal to the ratio of the sum of the cubic capacities of the pumps of the second and first group respectively.

Further particular features and advantages of the invention will become apparent from the following description, reference being made to the accompanying drawings which are given by way of example without any implied limitation.

FIG. 1 is the diagram of a supply device in accordance with the invention, and

FIG. 2 is a diagram showing the conditions of operation of the device of FIG. 1.

The device shown in the drawings includes:

a single driving engine 1 of the Diesel type;

four pumps with constant cubic capacity (also called constant flow pumps for a predetermined speed of rotation) 2, 3, 4, 5.

a fluid reservoir 6,

a first distributor 7, a second distributor 8 and a third distributor 9, each having two positions,

a first circuit of utilisation 10 and a second circuit of utilisation 11.

The driving shafts 12, 13, 14, of the pumps 2, 3, 4, 5 are rigidly fixed in rotation with pinions 16, 17, 18, 19 respectively. Likewise, a pinion is rigidly fixed in rotation with the output shaft 21 of the engine 1. Pinion 17 meshes with pinions 16 and while pinion 18 meshes with pinions 19 and 20.

A conduit 22 connects the first distributor 7 with the first circuit of utilisation 10, while a conduit 23 connects said distributor 7 with the reservoir 6 and a return conduit connects circuit 10 with reservoir 6.

The pump 2 is connected to the reservoir 6 by its suction conduit 25 and to conduit 22 by its discharge conduit 26. The pump 3 is connected to reservoir 6 by its suction conduit 27 and to the first distributor 7 by its discharge conduit 28.

The pump 4 is connected to reservoir 6 by its suction conduit 29 and to the second distributor 8 by its discharge conduit 30. The second distributor 8 is in turn connected to the third distributor 9 by conduit 31, while the second circuit of utilisation 11 is connected to the reservoir 6 by return conduit 32 and to the third distributor by conduit 33. A conduit 50 connects the second distributor 8 to the reservoir 6.

The pump is connected to the reservoir 6 by its suction conduit 34 and to the conduit 31 by its discharge conduit 35. Finally, joining conduit 36 connects the third distributor 9 to the conduit 22.

Two rams 38 and 39 having respective sections S and S are coupled to distributor 7 and their effect opposes that of a first spring 40, also coupled to the said distributor. These rams are respectively connected to conduits 22 and 31 by conduits 41, 42.

Similarly, two rams 43, 44 of respective sections S S are coupled to distributor 8 and their effect opposes that of a second spring 45, also coupled to the said distributor. An auxiliary conduit 46 connecting the conduits 22 and 31 and a shuttle valve 47 being placed on said auxiliary conduit 46, the ram 44 is connected to the outlet of the shuttle valve 47 by conduit 48, while ram 43 is connected to the conduit 31 by conduit 49.

Preferably, the following equalities are verified:

38 39 2 3) 5 in these equalities, C C C and C are the cubic capacities of pumps 2, 3, 4 and 5 respectively.

In the first distributor 7:

the first position corresponds to the predominance of the effect of spring 40 on the effects of rams 38, 39, to the placing in communication of conduits 22 and 28 and to the obturation of conduit 23 at the level of this distributor, and

the second position, to the placing in communication of conduits 23 and 28 and to the obturation of this conduit 22 at the level of this distributor.

4 In the second distributor 8: the first position corresponds to the predominance of the effect of spring 45 on the effects of rams 43, 44, to the placing in communication of conduits 30 and 31 and to the obturation, at the level of this distributor, of conduit 50, and the second position, to the placing in communication of conduits 30 and 50 and to the obturation of conduit 31 at the level of this distributor.

Finally, in the third distributor 9 the first position corresponds to the placing in communication of conduits 31 and 33 and to the obturation of conduit 36, at the level of this distributor, and

the second position corresponds to the placing in communication of conduits 31 and 36 and to the obturation of conduit 33 at the level of this distributor. A member for voluntary control, in the present case manual control, is furthermore coupled to the third distributor 9.

It is also important to specify that the maximum power of engine 1 is less than the sum of the maximum power required for driving pumps 2, 3, 4 and 5.

The graph of FIG. 2 shows the zones of variation of the pressure P prevailing in the conduit 22, at the input of circuit 10, in accordance with the values of pressure P prevailing in the conduit 33 at the input of circuit 11.

Two first segments of straight line AB and BC which cross at B, the first segment AB being parallel to 0p and the segment BC to 0p delimit the maximum discharge pressures of pumps 2 to 5. Pressures pA and pC in A and C are equal to 320 kgp/cm for example. Two other segments of straight line cross at D, in the zone OABC, segment DE being parallel to Op, and segment DF being parallel to Op Another segment of straight line GH is parallel to DF and corresponds to a pressure pI-l superior to pH but inferior to pC. Finally, two segments of straight line, inclined with respect to 0p and Op extend from segment AB to point G as far as segment JKG is concerned, and from point K located on JG to point M on BC as far as segment KLM is concerned. It is important to note that ED cuts BC at N, and FD cuts AB at P. The various segments of straight lines delimit zones having distinct surfaces. Pumps 2, 3, 4 and 5 having respectively outflows Q Q Q and Q the zones of flow correspond to the stages of operation designated hereinafter.

In a conventional solution, the jacks 39 and 44 do not exist:

zone EDFO, (Q Q supplying circuit 10, (Q,

Q supplying circuit 11 (distributor 9 in its first position); zone AEDP, Q only supplying circuit 10, (Q Q supplying circuit 11;

zone NCFD (Q Q supplying circuit 10, Q only supplying circuit 11;

zone PDNB, Q supplying circuit 10 and Q supplying circuit 1 1.

The solution suggested takes into account segments JG and KM. But these segments correspond (distributor in its second position):

JG to the equation P X (Q Q P X (Q Q P I wherein P is the maximum power of engine 1,

KM, to equation P X (Q Q P X Q P 1 The first equation means that before placing in communication the discharge of pump 4 (conduit 30) with the reservoir 6 by means of the second distributor 8, the sum of the power of pumps 2 to 5 (product of the pressure by the outflow) is equal to the maximum power P of engine 1.

The second equation means that after placing in communication the discharge of pump 4 with the reservoir 6, but before putting in communication discharge of pump 3 with the reservoir 6, the sum of the power of pumps 2, 3 and 5 is still equal to P. Finally, in the suggested solution, the two following zones are distinguished:

zone AJCI-IO, (Q Q supplying circuit 10, and

(Q, Q Supplying circuit 11;

zone l-IGKMG (Q Q supplying circuit and Q only supplying circuit 11;

zone .IBMK, Q supplying circuit 10, and Q supplying circuit 11.

If Q Q Q and if Q Q we note that the suggested solution permits increases in the supply flows of circuits l0 and 11, respectively equal to:

an increase of 33 percent on the hatched zone AJKLE for circuit 10, an increase of 100 percent on the hatched zone DGHF at superior ranges of pressure.

As a matter of fact, in order to be sure that in all the cases of operation the sum of the driving power of the pumps was at the most equal to the maximum power P of the engine 1, it was imperatively necessary with the conventional solution, to limit the pressures to the values P for I and P for P whilst with the suggested solution, the segments of straight line JG and KM could be reached for circuit 10, and GH for circuit 11, hence a larger range of pressure.

It is to be noted that equations (1) and (2) may also read:

P11 a Pro A (1 bis) P11 b P10 B 2 bis) From (1 bis) and (2 bis) are easily obtained the relative values of the sections of rams 38, 39, 43 and 44:

ass 39 b It is obvious that since the third distributor is placed in its second position (position shown) the pumps then exclusively supply circuit 10.

In addition it is specified that, generally, the second distributor 8 puts the discharge conduit of pump 4 in communication with the reservoir 6 before the first distributor 7 puts in communication with reservoir 6 the discharge conduit of pump 3, this being obtained by selecting the characteristics of the control rams of distributors 7 and 9 and springs 40 and 45.

In summary, in the case of separate supply of circuits 10 and 11 (third distributor 9 in its first position), the solution suggested makes it possible to obtain a gain of flow for the operations corresponding to the hatched zones of the diagram of FIG. 2. In the example shown, these gains of flow are 33 percent and 100 percent for the circuits 10 and 11 respectively. It is then obvious that adopting the solution suggested allows an important increase in the output of the supply device, while still not exceeding the value P of the maximum power of engine 1.

In the present specification, the word distributor has been taken in a broad sense and designates a distributing valve of any type which directs the fluid in a predetermined direction; in practice this valve may consist either in a slide valve or in a controlled valve.

What is claimed is:

1. Device feeding two circuit systems with pressurised fluid, constituted by:

a fluid tank,

a first group of pumps each with constant flow,

a first of the two circuit systems,

a first feed conduit connecting a first pump belonging to the first group of pumps, to the first circuit system,

a first two-way distributor disposed in the first feed conduit ensuring, in its first position, the continuity of the first feed conduit and, in its second position, the communication of that part of the feed conduit included between the first pump and the first distributor with the tank,

a second group of pumps each with constant outflow,

the second of the two circuit systems,

a second feed conduit connecting a second pump belonging to the second group of pumps, to the second circuit system,

a second two-way distributor disposed in the second feed conduit ensuring, in its first position, the continuity of the second feed conduit and, in its second position, the communication of that part of the sec ond feed conduit, included between the second pump and the second distributor with the tank,

a third two-way distributor disposed in the second feed conduit between the second distributor and the second circuit system and a connecting conduit which connects the third distributor to that part of the first feed conduit included between the first distributor and the first circuit system, whilst the third distributor in its first position, establishes communication between the second distributor and the second circuit system and, in its second position, establishes communication between the second distributor and the connecting conduit and obturates that part of the second feed conduit connected directly to the second feed circuit, well as a first return member are coupled to the first distributor each of the first and second control members having an effect opposing that of the first return member, and said latter having an effect tending to place this first distributor in its first position, whilst third and fourth control members, as well as a second return member are coupled to the second distributor each of the third and fourth control members having an effect opposing that of the second return member, and said latter having an effect tending to place this second distributor in its first position, a first control conduit connecting that part of the first feed conduit, included between the first distributor and the first circuit system to the first control member, a second control conduit connecting that part of the second feed conduit included between the second distributor and the third distributor to the second control member, an auxiliary conduit connecting that part of the first feed conduit included between the first distributor and the first circuit system to that part of the second feed conduit included between the second and third distributors, a shuttle valve disposed in said auxiliary conduit, and a third control conduit connecting that part of the second feed conduit included between the second and third distributors to the third control member, and a fourth control conduit connecting the output of the shuttle valve to the fourth control member and finally the pumps of the first and second groups of pumps are coupled t a i l d i motor, h maximum 3. Device according to claim 1, characterized in that power f which is lower than the sum of the maxi the third and fourth control members each consists ot a hydraulic ram the ratio of the cross-sections of said powers the vanfjus pumps jacks is equal to the ratio of the sum of the cubic capac- 2. Device according to claim 1, characterized in that ities f the pumps f the Second and fi t group reshecthe first and second control members each consists of a tively.

hydraulic ram the ratio of the cross-sections of said Device according t0 Claim Characterized. in that j k i equal to the ratio f the sum f the cubic cahao the third and fourth control members each consists of a ities of the pumps of the first group and the sum of the hydraphc ram the ratio of the crosysectlon? of sald l0 rams is equal to the ratlo of the sum of the cubic capaccubic capacities of the pumps of the Second group less ities of the pumps of the second and first group respecthe value of the cubic capacity of the second pump of i l the said second group respectively. 

1. Device feeding two circuit systems with pressurised fluid, constituted by: a fluid tank, a first group of pumps each with constant flow, a first of the two circuit systems, a first feed conduit connecting a first pump belonging to the first group of pumps, to the first circuit system, a first two-way distributor disposed in the first feed conduit ensuring, in its first position, the continuity of the first feed conduit and, in its second position, the communication of that part of the feed conduit included between the first pump and the first distributor with the tank, a second group of pumps each with constant outflow, the second of the two circuit systems, a second feed conduit connecting a second pump belonging to the second group of pumps, to the second circuit system, a second two-way distributor disposed in the second feed conduit ensuring, in its first position, the continuity of the second feed conduit and, in its second position, the communication of that part of the second feed conduit, included between the second pump and the second distributor with the tank, a third two-way distributor disposed in the second feed conduit between the second distributor and the second circuit system and a connecting conduit which connects the third distributor to that part of the first feed conduit included between the first distributor and the first circuit system, whilst the third distributor in its first position, establishes communication between the second distributor and the second circuit system and, in its second position, establishes communication between the second distributor and the connecting conduit and obturates that part of the second feed conduit connected directly to the second feed circuit, well as a first return member are coupled to the first distributor each of the first and second control members having an Effect opposing that of the first return member, and said latter having an effect tending to place this first distributor in its first position, whilst third and fourth control members, as well as a second return member are coupled to the second distributor each of the third and fourth control members having an effect opposing that of the second return member, and said latter having an effect tending to place this second distributor in its first position, a first control conduit connecting that part of the first feed conduit, included between the first distributor and the first circuit system to the first control member, a second control conduit connecting that part of the second feed conduit included between the second distributor and the third distributor to the second control member, an auxiliary conduit connecting that part of the first feed conduit included between the first distributor and the first circuit system to that part of the second feed conduit included between the second and third distributors, a shuttle valve disposed in said auxiliary conduit, and a third control conduit connecting that part of the second feed conduit included between the second and third distributors to the third control member, and a fourth control conduit connecting the output of the shuttle valve to the fourth control member and finally the pumps of the first and second groups of pumps are coupled to a single drive motor, the maximum power of which is lower than the sum of the maximum powers of the various pumps.
 2. Device according to claim 1, characterized in that the first and second control members each consists of a hydraulic ram the ratio of the cross-sections of said jacks is equal to the ratio of the sum of the cubic capacities of the pumps of the first group and the sum of the cubic capacities of the pumps of the second group, less the value of the cubic capacity of the second pump of the said second group respectively.
 3. Device according to claim 1, characterized in that the third and fourth control members each consists of a hydraulic ram the ratio of the cross-sections of said jacks is equal to the ratio of the sum of the cubic capacities of the pumps of the second and first group respectively.
 4. Device according to claim 2, characterized in that the third and fourth control members each consists of a hydraulic ram the ratio of the cross-sections of said rams is equal to the ratio of the sum of the cubic capacities of the pumps of the second and first group respectively. 